Rogue One has proved that you can do a prequel-sequel to the original trilogy and the prequels, and not only have a hit movie but have some surprises along the way. Though the appearance of Darth Vader was known, a few things that happened in the movie concerning him weren’t. Mainly, that he has his own castle on Mustafar.
For those who recall, it was this planet that featured the epic final battle between Anakin Skywalker and Obi-Wan Kenobi. Of which Kenobi one the fight, and Anakin was burned severely by a river of lava. So many were surprised when the movie not only went there, but showed that Vader has his own alcove/castle there where he apparently rested and healed when not in service to the Emperor. But, why have this castle at all?
Well, Rogue One’s co-production designer Doug Chiang talked about the thought process behind this. For the team, they wanted to not only make a castle for Vader, but explain why it would exist. The idea of him healing and meditating there was the key inspiration that made it work. Then, when they thought about design itself, they wanted to make it look as if it was trying to “tune” into the Dark Side of the Force. Thus why it looked like a black tuning fork.
Funnily enough, this isn’t the first time a castle for Vader was made. Originally, it was supposed to appear in Empire Strikes back, but it never got out of concept designs, and never made it into the script. At least now, we know where Vader was when he wasn’t…well…being Vader.